The Big Dig


Like the filling of Back Bay over 100 years ago, the Big Dig has transformed Boston – and yet even more awaits us. Rather than waiting a century to celebrate this incredible transformation made possible by waves of engineering breakthroughs, which ensured that the 1990s were a time of Boston downtown growth (and not chaos), it is time to step back and recognize the massive 30 year project for what it has already created in our physical and social landscape.

Stop the Highways! Start the Impossible!
The Big Dig began in the late 1960s with a grassroots movement to stop building highways through Boston and Cambridge neighborhoods. In 1970, Governor Frank Sargent stopped the juggernaut poised to ram the Southwest Expressway and Inner Belt through the City. He instituted a review of Eastern Massachusetts transportation in a participatory planning process that revolutionized the way transportation decisions are made.

Alan Altshuler, and later Jack Gifford, Director of the Boston Transportation Planning Review (BTPR), headed up the reviews involving hundreds of people and community organizations. Out of this came a resolution that no new highways were to be built unless they sought to build communities (not divide them), and minimized the impact on homes and businesses.

Vision of Change
Fred SalvucciThe Big Dig then took shape when Fred Salvucci sold Governor Dukakis, and all of us, on a vision of vastly expanded traffic capacity, a city reconnected to its waterfront, and mitigation efforts unheard of in the old days of highway engineer hegemony.

The task seemed impossible though. How do you develop a new highway system underground, and keep the city going and growing through the minimum 10 years of construction? It would take some major innovations in construction, engineering, civic participation and leadership to make this happen.

Construction, Engineering and Design
Next came making the impossible possible: reconfiguring Boston’s underground utility infrastructure; building a vast tunnel network between slurry walls with two decks of traffic flowing overhead; freezing seven acres of soil to stabilize it for digging beneath a spiderweb of railroad tracks; “jacking” a 30,000 ton prefabricated road bed through that soil; designing a work of art to cross the Charles; and maintaining surface traffic throughout.

All this, and much more, was made possible by at least five major innovations in engineering, construction and design. Expanding on relevant models from smaller, but similar projects around the world, the engineers developed major innovations. Now, engineers visit Boston for inspiration and implement breakthroughs found here to use for their own projects.